Cleaning compositions in pouch form have become increasingly popular among consumers. In the production process of such pouches, it may occur that a proportion of them do not comply with the required manufacture specifications and are therefore not suitable for sale. This could be the case for pouches produced during the start up, i.e., before the process reaches a steady state, and shut down of the process.
There is a need for dealing with these “non-suitable” pouches (herein also referred as “waste” or “rejects”) for economic and more importantly, environmental reasons. The nature of the pouches makes this a complex issue. Usually pouches are constituted of a water-soluble enveloping material and a cleaning composition, having very different chemical and physical properties from one another. This complexity is increased when the pouches have more than one compartment, especially if the compartments contain compositions in different physical forms (solid and liquid) or compositions comprising incompatible ingredients.
Cleaning compositions can comprise bleach, in particular inorganic bleach, such as sodium percarbonate. Usually the bleach is found at relative high weight concentration. Sodium percarbonate is a key cleaning and stain removal technology delivering good removal of bleachable stains, at affordable cost; however incorporation of this ingredient into cleaning formulations can have associated stability issues. Sodium percarbonate is an unstable chemical ingredient, which, in presence of moisture can decompose generating initially hydrogen peroxide and subsequently water and molecular oxygen. This decomposition reaction is exothermic and autocatalytic. The stability of sodium percarbonate is more challenging in the case of phosphate-free cleaning compositions. Traditional cleaning compositions contain phosphate. In addition to being a good cleaning active, phosphate is a good moisture trap that contributes to the processability and stability of the cleaning composition. In the case of phosphate-free compositions, it is not only that the phosphate is not there to trap moisture but also that the phosphate is usually replaced by other cleaning actives that can have hygropscopic nature, in detriment of the processability and stability of the resulting composition.
Water-soluble pouches containing solid and liquid compositions in different compartments present an added complication if the pouch needs to be recycled. A way to recycle the pouch could be the separation of the solid and the liquid compositions but this process is time consuming and costly. Alternatively, the solid and liquid compositions can be mixed but they can interact with each other and can have stability issues when mixed. This could occur during the processing and storage of the mixture. It will determine the storage time and conditions thereby reducing the flexibility of the recycling process.
In light of the above discussion there is the need for an efficient process for recycling water-soluble pouches containing bleach and compositions in solid and liquid forms.